Environmental Engineering Reference
In-Depth Information
$13/bbl total. Since most oil wells produce 5-10 bbl of water for every 1 bbl of oil,
this results in a cost structure in which there is $65-$130 of water cost per $100 of
oil value produced. The resulting situation is not economically viable for treating
all the water and can only be applied to a very limited quantity.
Offshore EU North Sea
:
The authors have developed technology for use offshore,
where generally a two- to four-step treatment train is bolted together. Unlike
onshore treatment trains, the treated water does not have to be desalinated, as it
will be injected into the already salty oceans. Systems developed by the authors
have managed offshore produced water at costs between $2.80/bbl and $7.10/bbl.
The variable nature in offshore treatment, unlike onshore, stems from the com-
plexity of the chemistry to be treated and the regulatory compliance standards
that the company must meet for discharge.
The economics of produced water is the difference in the value of all wells. Nearly all oil
and gas wells are brought out of production, or “shut in” because of the cost of treating the
waters nearly always increases over the life of the well, while the volume of hydrocarbons
declines. Eventually, the valuable hydrocarbons recovered are less than the costs of operat-
ing the well, which is primarily due to the escalating costs of managing the produced water.
8.5 Summary
Produced water is likely the largest industrial waste stream in the world. The need to
treat produced water is limited by the ability to deep well inject onshore and discharge
to the ocean offshore. However, advanced technologies are being developed to help treat
produced water where applicable. Osorb is a nanoengineered organosilica that expands
in contact with organic solutes but does not absorb water. The characteristics of Osorb
have been shown to be optimal for the removal of free and dissolved organics from pro-
duced water. The extraction of dissolved species is particularly unique compared with
other water treatment technologies. Osorb has high afinity for dissolved BTEX and hydro-
carbons. Additionally, extraction of polar organics also appears feasible, especially when
altering the surface of the nanoengineered organosilica to improve the selectivity for polar
compounds. Osorb has been both successfully manufactured at a pilot scale and tested
using a 60 gpm system, which indicates good promise for nanoscale, engineered materials
since a pathway exists for scale up. The economics of produced water treatment will favor
a status quo in the near future assuming a constant regulatory environment.
Acknowledgments
The authors wish to thank the efforts of Justin Keener and Scott Buckwald of Produced
Water Absorbents on the design, build out, and testing of the produced water pilot treat-
ment systems. Funding for this work was provided by the National Science Foundation
SBIR program (grant no. 1013263).
